Jinhao Qiu

Learn More
Piezoelectric actuators can offer high resolution of displacement and this makes them suitable for precise driving tasks. However, most piezoelectric actuators are made of piezoceramics which have a major drawback related to their natural hysteresis nonlinearity. To compensate the hysteresis nonlinearity of piezoelectric actuators, many hysteresis models(More)
This paper describes an approach to controlling the force generated by a piezoelectric actuator (PEA) accurately without using any force sensor. A model PEA is proposed that includes a new asymmetric hysteresis operator and that takes the external force into account. A detection model is deduced that allows computation in real time of the PEA elongation and(More)
Piezoelectric actuators (PEAs) are commonly used as micropositioning devices due to their high resolution, high stiffness, and fast frequency response. Because piezoceramic materials are ferroelectric, they fundamentally exhibit hysteresis behavior in their response to an applied electric field. The positioning precision can be significantly reduced due to(More)
ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ ⅷ Integrated structure᎐control design of a two-link flexible robot arm is investigated in this article. The whole arm consists of two flexible links, a fixed joint, a moving joint, and a tip load. The arm is driven by the torque motors at the two joints to reach predefined tip positions and(More)
A new wave energy flow (WEF) map concept was proposed in this work. Based on it, an improved technique incorporating the laser scanning method and Betti's reciprocal theorem was developed to evaluate the shape and size of damage as well as to realize visualization of wave propagation. In this technique, a simple signal processing algorithm was proposed to(More)
The intrinsic hysteresis behavior of piezoelectric material limits the tracking control accuracy of the actuators. This paper describes a tracking control method for piezoelectric actuators based on the combination of feedforward and feedback loops. The hysteresis of piezoelectric actuators is linearized in feedforward loop with an inverse hysteresis model(More)
Pure-phase (K, Na)NbO3 (KNN) powders with orthorhombic symmetry were successfully synthesized by solvothermal method using isopropanol as solvent, without the addition of water. The as-prepared powders were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry to show the variation of phase, morphology, size(More)
KTa(x)Nb(1_x)O3 (KTN) particles with an orthorhombic perovskite structure were synthesized via a high temperature mixing method (HTMM) under hydrothermal and solvothermal conditions. The obtained products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy(More)
Simultaneous structural-control optimization of a coupled structural-acoustic enclosure is investigated in this paper. The whole system has a rectangular parallelepiped sound field of which the entire bottom face and the partial top face are covered with two elastic plates while the other boundaries are enclosed with rigid walls. Two point forces applied on(More)
Structural modification, especially the stabilization of metastable phases at room temperature, has emerged as an effective strategy to understand their stabilization mechanism and improve their functional properties. In this work, a facile solvothermal approach is developed to synthesize metastable sodium niobate (NaNbO3) crystals with the cubic symmetry.(More)